In a mobile communication system of an LTE-Advanced system, which is a succeeding communication system of a long term evolution (LTE) system, a “relay node RN” provided with a similar function to a radio base station DeNB (Donor eNB) can be connected between a mobile station UE and the radio base station DeNB.
Such a mobile communication system of an LTE-Advanced system is configured such that an E-UTRAN radio access bearer (E-RAB) is set between the mobile station UE and a core node (CN), a Uu radio bearer is set between the mobile station UE and the relay node RN, a Un radio bearer is set between the relay node RN and the radio base station DeNB, and an S1 bearer is set between the radio base station DeNB and the code node CN.